I think this is a game jam master piece. You nailed so much in the little game. The atmosphere was beyond me. The music mixed so well the the art it just made the game come to life! I'm not even sure what to say. The game was beyond any jam submission I think I've played so far. If only I got to see the end. I just could pass the last level...
I believe you can improve on the background of the game a bit after the jam. Though the art fit really well, I feel as if it can be polished a bit more: trees blowing in the wind, trash rolling on the ground. Your game really banks off of atmosphere and it would be cool to see you take it all the way with it. Awesome submission...